Phytomedicines prepared from Arnica flowers inhibit the transcription factors AP-1 and NF-kappaB and modulate the activity of MMP1 and MMP13 in human and bovine chondrocytes

Anti-inflammatory effects of Arnica montana (mother tincture and homeopathic dilutions) in various cell models

ETHNOPHARMACOLOGICAL RELEVANCE

The plant Arnica montana L. has been shown to alleviate inflammation, pain and swelling associated with trauma, and post-operative clinical conditions, yet the mechanism of action is not well understood.

AIM OF THE STUDY

The study was designed to investigate the effect of Arnica montana (A. montana) mother tincture and homeopathic dilutions on inflammation markers, oxidative stress and cell migration in diverse cell culture models.

MATERIALS AND METHODS

We tested A. montana mother tincture and a range of homeopathic dilutions in different human and murine cell culture models to demonstrate their anti-inflammatory properties by measuring the inflammatory markers: tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule (ICAM-1), reactive oxygen species (ROS) and cell migration. The inflammatory markers were measured by ELISA assays. The intracellular oxidative stress (ROS) in microglial cells was measured using Deep Red CellROX probe. The cell migration was examined by wound healing using the Oris Cell migration assay.

RESULTS

These data showed the ability of A. montana (mother tincture and mainly 1C dilution) to significantly reduce TNFα production in inflamed macrophages compared with vehicle (control). They significantly reduced both IL-6 and MCP-1 in inflamed human microglial cells and significantly decreased COX-2 expression in inflamed murine fibroblasts. Moreover, A. montana mother tincture reduced the cell migration whereas 9C dilution significantly enhanced the migration of fibroblast cells compared with vehicle. The expression of ICAM-1 was significantly reduced with A. montana mother tincture and 1C, 3C, 5C, and 9C dilutions in inflamed human endothelial cells compared with vehicle. A. montana mother tincture and 1C, 3C, 5C and 9C dilutions induced a significant and consistent effect on ROS production in inflamed murine microglial cells. A. montana 1C had the largest impact on ROS production.

CONCLUSIONS

Mother tincture and 1C dilution of A. montana showed anti-inflammatory properties assessed by measurement of several markers (pro-inflammatory cytokines, adhesion molecule, ROS) in various human and murine cell models. In addition, A. montana 3C, 5C, 9C dilutions have anti-inflammatory and antioxidant effects as highlighted on both primary endothelial cells and murine microglial cells.

Arnica montana L.: Doesn't Origin Matter?

Arnica montana L. (Asteraceae) has a long and successful tradition in Europe as herbal medicine. Arnica flowers (i.e., the flowerheads of Arnica montana) are monographed in the European Pharmacopoeia (Ph. Eur.), and a European Union herbal monograph exists, in which its use as traditional herbal medicine is recommended. According to this monograph, Arnica flowers (Arnicae flos Ph. Eur.) and preparations thereof may be used topically to treat blunt injuries and traumas, inflammations and rheumatic muscle and joint complaints. The main bioactive constituents are sesquiterpene lactones (STLs) of the helenanolide type. Among these, a variety of esters of helenalin and 11α,13-dihydrohelenalin with low-molecular-weight carboxylic acids, namely, acetic, isobutyric, methacrylic, methylbutyric as well as tiglic acid, represent the main constituents, in addition to small amounts of the unesterified parent STLs. A plethora of reports exist on the pharmacological activities of these STLs, and it appears unquestioned that they represent the main active principles responsible for the herbal drug's efficacy. It has been known for a long time, however, that considerable differences in the STL pattern occur between A. montana flowers from plants growing in middle or Eastern Europe with some originating from the Iberic peninsula. In the former, Helenalin esters usually predominate, whereas the latter contains almost exclusively 11α,13-Dihydrohelenalin derivatives. Differences in pharmacological potency, on the other hand, have been reported for the two subtypes of Arnica-STLs in various instances. At the same time, it has been previously proposed that one should distinguish between two subspecies of A. montana, subsp. montana occurring mainly in Central and Eastern Europe and subsp. atlantica in the southwestern range of the species distribution, i.e., on the Iberian Peninsula. The question hence arises whether or not the geographic origin of Arnica montana flowers is of any relevance for the medicinal use of the herbal drug and the pharmaceutical quality, efficacy and safety of its products and whether the chemical/pharmacological differences should not be recognized in pharmacopoeia monographs. The present review attempts to answer these questions based on a summary of the current state of botanical, phytochemical and pharmacological evidence.

Nitrogen Fertilization and Solvents as Factors Modifying the Antioxidant and Anticancer Potential of Arnica montana L. Flower Head Extracts

Arnica montana L. is one of Europe's endemic endangered medicinal plants, with diverse biological activities commonly used in medicine, pharmacy, and cosmetics. Its flower heads are a rich source of raw material, with antibacterial, antifungal, antiseptic, anti-inflammatory, antiradical, antioxidant, and antitumor properties. The objective of the present study was (i) to characterize the chemical composition of flower heads of A. montana plants cultivated under nitrogen fertilization, (ii) to identify the impact of the nitrogen fertilization and extraction method (water, ethanol) on the antioxidant activity of extracts, and (iii) to determine the role of different nitrogen doses applied during plant cultivation and different extraction methods in the anticancer activity of the extracts through analysis of apoptosis and autophagy induction in HT29, HeLa, and SW620 cell lines. The present study shows that nitrogen is a crucial determinant of the chemical composition of arnica flower heads and the antioxidant and anticancer activity of the analyzed extracts. Nitrogen fertilization can modify the composition of pharmacologically active substances (sesquiterpene lactones, flavonoids, essential oil) in Arnicae flos. The content of sesquiterpene lactones, flavonoids, and essential oil increased with the increase in the nitrogen doses to 60 kg N ha^-1 by 0.66%, 1.45%, and 0.27%, respectively. A further increase in the nitrogen dose resulted in a decrease in the content of the analyzed secondary metabolites. Varied levels of nitrogen application can be regarded as a relevant way to modify the chemical composition of arnica flower heads and to increase the anticancer activity, which was confirmed by the increase in the level of apoptosis with the increase in fertilization to a level of 60 kg N ha^-1. The fertilization of arnica plants with low doses of nitrogen (30 and 60 kg N ha^-1) significantly increased the LOX inhibition ability of the ethanol extracts. The present study is the first report on the anticancer activity of A. montana water extracts, with emphasis on the role of water as a solvent. In further studies of factors modifying the quality of Arnicae flos, attention should be paid to the simultaneous use of nitrogen and other microelements to achieve synergistic results and to the possibility of a more frequent use of water as a solvent in studies on the biological activity of A. montana extracts.

Differentiation and Propagation Potential of Arnica montana L. Achenes as a Consequence of the Morphological Diversity of Flowers and the Position of Flower Heads on the Plant

Arnica montana L. is a very important medicinal plant and simultaneously a European endemic endangered plant species. The morphological features and details of seed development and achene variability are poorly recognized. The aim of this study was to determine the impact of the achene position in the infructescence and the location of the inflorescence on the plant on the (i) morphological characteristics and germination ability of achenes, and (ii) recruitment of seedlings and their biometric features. Infructescences containing fully ripe achenes were randomly collected from A. montana individuals for the measurements and the germination experiment. Scanning electron microscopy, fluorescence microscopy, and light microscopy were used for characterization of flowers and achenes. The morphological traits of achenes and reproductive characteristics of A. montana were determined by the position of the achenes in the infructescence and the location of the inflorescence on the plant. The surface of arnica achenes is equipped with non-glandular and glandular trichomes, which is very rarely presented in species of the family Asteraceae. It is possible that the fluid-containing glandular trichomes are a source of essential oils. The peripherally located achenes were longer, thinner, and lighter. They were characterized by lower embryo weight, lower embryo/achene weight ratio, and lower germination capacity in comparison to the centrally located ones. The results presented in this article fill the gap in the knowledge of the morphology of achenes and the biology of the species, and provide information that can help in breeding programs, active protection, and field cultivation.

Comparing Wild and Cultivated Arnica montana L. from the Italian Alps to Explore the Possibility of Sustainable Production Using Local Seeds

Arnica montana L. is an alpine herbaceous plant typical of nutrient-poor grasslands. It is a popular medicinal plant for the treatment of bruises, cuts and pain, and it is also an endangered alpine species. For this reason, the sustainable production of inflorescences instead of the spontaneous collection of plant material, coupled with the use of local ecotypes, should be incentivized. Inflorescences of a wild accession of arnica were compared versus an accession cultivated in Valsaviore (Italian Alps) in terms of seed germination performance and phytochemical characterization by high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC-MS) techniques. The germination percentage was high (>75%) for both cultivated and wild seeds. The NMR spectra of arnica extracts were very similar and confirmed the presence of sesquiterpene compounds, esters of helenaline and dehydroelenaline. A significant high percentage of acetic acid methyl ester (38 μg/g) and the 2-methyl methyl ester of propanoic acid (31 μg/g) were found in cultivated arnica and were probably associated with fermentation processes linked to the traditional method of air drying on a trellis. The possibility of growing A. montana and a controlled local first transformation are important to incentivize local, good quality and sustainable production. The growing of seedlings “in loco” could be of great interest both for farmers and for natural conservation purposes.

Anti-Inflammatory Activity of the Compositae Family and Its Therapeutic Potential

Compositae is the largest family of flowering plants, with more than 1600 genera and 22 000 species. It has many economic uses in foods, cosmetics, and pharmaceutics. The literature reports its numerous medicinal benefits and recognized anti-inflammatory activity. Thus, this study evaluated the technological trends of anti-inflammatory activity of Compositae, based on the survey of scientific databases, articles, and patents, as well as the website of the Brazilian National Health Regulatory Agency (ANVISA), which is responsible for registering and controlling of healthcare and cosmetic products in the Brazil. The survey was conducted between 2008 and 2018, in the databases Science Direct, Lilacs, PubMed, and Web of Science (main collection), as well as the SciELO Citation Index. The patent survey was carried out on the basis of the Derwent Innovations Index, an important source for worldwide patent consultation, which covers 20 y of registered patents. Despite the numerous studies involving species of the Compositae family in different models of anti-inflammatory activity, there are few records of patents or products on the market from these species for that purpose. Some species have a traditional use and are present even in the Phytotherapic Summary of the Brazilian Pharmacopeia. This review confirms the therapeutic potential of Compositae for the development of anti-inflammatory drugs and reinforces the need to develop competencies and reduce technological bottlenecks to promote research and innovation in biodiversity products.

Type III Secretion System of Pseudomonas aeruginosa Affects Matrix Metalloproteinase 12 (MMP-12) and MMP-13 Expression via Nuclear Factor κB Signaling in Human Carcinoma Epithelial Cells and a Pneumonia Mouse Model

The type III secretion system (T3SS) in Pseudomonas aeruginosa has been linked to severe disease and poor clinical outcomes in animal and human studies. We aimed to investigate whether the ExoS and ExoT effector proteins of P. aeruginosa affect the expression of matrix metalloproteinase 12 (MMP-12) and MMP-13 via nuclear factor κB (NF-κB) signaling pathways. To understand the T3SS, we used ΔExoS, ΔExoT, and ExsA::Ω mutants, as well as P. aeruginosa strain K (PAK)-stimulated NCI-H292 cells. We investigated the effects of ΔExoS, ΔExoT, and ExsA::Ω on the development of pneumonia in mouse models. We examined the effects of ΔExoS, ΔExoT, and ExsA::Ω on MMP-12 and MMP-13 production in NCI-H292 cells. ΔExoS and ΔExoT markedly decreased the neutrophil count in bronchoalveolar lavage fluid, with a reduction in proinflammatory mediators, MMP-12, and MMP-13. ΔExoS and ΔExoT reduced NF-κB phosphorylation, together with MMP-12 and MMP-13 expression in PAK-infected mouse models and NCI-H292 cells. To conclude, P. aeruginosa infection induced the expression of MMPs, and P. aeruginosa T3SS appeared to be a key player in MMP-12 and MMP-13 expression, which is further controlled by NF-κB signaling. These findings might be useful in devising a novel therapeutic approach to chronic pulmonary infections that involves decreasing the ExoS and ExoT levels.

Arnica montana effects on gene expression in a human macrophage cell line. Evaluation by quantitative Real-Time PCR

BACKGROUND

Arnica montana is a popular traditional remedy widely used in complementary medicine, also for its wound healing properties. Despite its acknowledged action in clinical settings at various doses, the molecular aspects relating to how A. montana promotes wound healing remain to be elucidated. To fill this gap, we evaluated the whole plant extract, in a wide range of dilutions, in THP-1 human cells, differentiated into mature macrophages and into an alternative IL-4-activated phenotype involved in tissue remodelling and healing.

METHODS

Real-time quantitative Reverse Transcription Polymerase Chain Reaction (PCR) analysis was used to study the changes in the expression of a customized panel of key genes, mainly cytokines, receptors and transcription factors.

RESULTS

On macrophages differentiated towards the wound healing phenotype, A. montana affected the expression of several genes. In particular CXC chemokine ligand 1 (CXCL1), coding for an chief chemokine, exhibited the most consistent increase of expression, while also CXC chemokine ligand 2 (CXCL2), Interleukin8 (IL8) and bone morphogenetic protein (BMP2) were slightly up-regulated, suggesting a positive influence of A. montana on neutrophil recruitment and on angiogenesis. MMP1, coding for a metalloproteinase capable of cleaving extracellular matrix substrates, was down-regulated. Most results showed non-linearity of the dose-effect relationship.

CONCLUSIONS

This exploratory study provides new insights into the cellular and molecular mechanisms of action of A. montana as a promoter of healing, since some of the genes it modifies are key regulators of tissue remodelling, inflammation and chemotaxis.

Medicinal plants used by Burundian traditional healers for the treatment of microbial diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Infectious diseases represent a serious and worldwide public health problem. They lead to high mortality, especially in non-developed countries. In Burundi, the most frequent infectious diseases are skin and respiratory (mainly in children) infections, diarrhea, added to malaria, HIV/AIDS and tuberculosis. Local population used mostly traditional herbal medicines, sometimes animal and mineral substances, to fight against these plagues.

OBJECTIVES

To survey in different markets and herbal shops in Bujumbura city, medicinal plants sold to treat microbial infections, with particular emphasis on the different practices of traditional healers (THs) regarding plant parts used, methods of preparation and administration, dosage and treatment duration.

MATERIALS AND METHODS

The ethnobotanical survey was conducted by interviewing, using a pre-set questionnaire, sixty representative healers, belonging to different associations of THs approved and recognised by the Ministry of Health. Each interviewed herbalist also participated in the collection of samples and the determination of the common names of plants. The plausibility of recorded uses has been verified through an extensive literature search.

RESULTS

Our informants enabled us to collect 155 different plant species, distributed in 51 families and 139 genera. The most represented families were Asteraceae (20 genera and 25 species), Fabaceae (14 genera and 16 species), Lamiaceae (12 genera and 15 species), Rubiaceae (9 genera and 9 species), Solanaceae (6 genera and 6 species) and Euphorbiaceae (5 genera and 6 families). These plants have been cited to treat 25 different alleged symptoms of microbial diseases through 271 multi-herbal recipes (MUHRs) and 60 mono-herbal recipes (MOHRs). Platostoma rotundifolium (Briq.) A. J. Paton (Lamiaceae), the most cited species, has been reported in the composition of 41 MUHRs, followed by Virectaria major (Schum.) Verdc (Rubiaceae, 39 recipes), Kalanchoe crenata (Andrews) Haw. (Crassulaceae, 37 recipes), Stomatanthes africanus (Oliv. & Hiern) R. M. King & H. Rob. (35 recipes), and Helichrysum congolanum Schltr. & O. Hoffm. (Asteraceae, 33 recipes). Regarding MOHRs, Pentas longiflora Oliv. (Rubiaceae) is the most important species with 19 recipes, followed by Kalanchoe crenata (Andrews) Haw. (Crassulaceae, 10 recipes), Gymnosporia senegalensis (Lam.) Loes. (Celastraceae, 9 recipes), Tetradenia riparia (Hochst.) Codd (Lamiaceae, 8 recipes) and Cardiospermum halicacabum L. (Sapindaceae, 6 recipes). Concerning the preparation and administration of recipes, our informants state to be able to adjust the doses based on the patient's age (child or adult) and/or his/her physiology (e.g. pregnancy).

CONCLUSION

This study indicates that medicinal plants are still widely used for the treatment of microbial diseases in Bujumbura city. However, there is much to do in this area, especially in the assessment and monitoring of the quality, effectiveness and safety of the different recipes preconised by Burundian traditional healers.

Topical herbal therapies for treating osteoarthritis

BACKGROUND

Before extraction and synthetic chemistry were invented, musculoskeletal complaints were treated with preparations from medicinal plants. They were either administered orally or topically. In contrast to the oral medicinal plant products, topicals act in part as counterirritants or are toxic when given orally.

OBJECTIVES

To update the previous Cochrane review of herbal therapy for osteoarthritis from 2000 by evaluating the evidence on effectiveness for topical medicinal plant products.

SEARCH METHODS

Databases for mainstream and complementary medicine were searched using terms to include all forms of arthritis combined with medicinal plant products. We searched electronic databases (Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, AMED, CINAHL, ISI Web of Science, World Health Organization Clinical Trials Registry Platform) to February 2013, unrestricted by language. We also searched the reference lists from retrieved trials.

SELECTION CRITERIA

Randomised controlled trials of herbal interventions used topically, compared with inert (placebo) or active controls, in people with osteoarthritis were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed the risk of bias of included studies and extracted data.

MAIN RESULTS

Seven studies (six different medicinal plant interventions; 785 participants) were included. Single studies (five studies) and non-comparable studies (two studies) precluded pooling of results.Moderate evidence from a single study of 174 people with hand osteoarthritis indicated that treatment with Arnica extract gel probably results in similar benefits as treatment with ibuprofen (non-steroidal anti-inflammatory drug) with a similar number of adverse events. Mean pain in the ibuprofen group was 44.2 points on a 100 point scale; treatment with Arnica gel reduced the pain by 4 points after three weeks: mean difference (MD) -3.8 points (95% confidence intervals (CI) -10.1 to 2.5), absolute reduction 4% (10% reduction to 3% increase). Hand function was 7.5 points on a 30 point scale in the ibuprofen-treated group; treatment with Arnica gel reduced function by 0.4 points (MD -0.4, 95% CI -1.75 to 0.95), absolute improvement 1% (6% improvement to 3% decline)). Total adverse events were higher in the Arnica gel group (13% compared to 8% in the ibuprofen group): relative risk (RR) 1.65 (95% CI 0.72 to 3.76).Moderate quality evidence from a single trial of 99 people with knee osteoarthritis indicated that compared with placebo, Capsicum extract gel probably does not improve pain or knee function, and is commonly associated with treatment-related adverse events including skin irritation and a burning sensation. At four weeks follow-up, mean pain in the placebo group was 46 points on a 100 point scale; treatment with Capsicum extract reduced pain by 1 point (MD -1, 95% CI -6.8 to 4.8), absolute reduction of 1% (7% reduction to 5% increase). Mean knee function in the placebo group was 34.8 points on a 96 point scale at four weeks; treatment with Capsicum extract improved function by a mean of 2.6 points (MD -2.6, 95% CI -9.5 to 4.2), an absolute improvement of 3% (10% improvement to 4% decline). Adverse event rates were greater in the Capsicum extract group (80% compared with 20% in the placebo group, rate ratio 4.12, 95% CI 3.30 to 5.17). The number needed to treat to result in adverse events was 2 (95% CI 1 to 2).Moderate evidence from a single trial of 220 people with knee osteoarthritis suggested that comfrey extract gel probably improves pain without increasing adverse events. At three weeks, the mean pain in the placebo group was 83.5 points on a 100 point scale. Treatment with comfrey reduced pain by a mean of 41.5 points (MD -41.5, 95% CI -48 to -34), an absolute reduction of 42% (34% to 48% reduction). Function was not reported. Adverse events were similar: 6% (7/110) reported adverse events in the comfrey group compared with 14% (15/110) in the placebo group (RR 0.47, 95% CI 0.20 to 1.10).Although evidence from a single trial indicated that adhesive patches containing Chinese herbal mixtures FNZG and SJG may improve pain and function, the clinical applicability of these findings are uncertain because participants were only treated and followed up for seven days. We are also uncertain if other topical herbal products (Marhame-Mafasel compress, stinging nettle leaf) improve osteoarthritis symptoms due to the very low quality evidence from single trials.No serious side effects were reported.

AUTHORS' CONCLUSIONS

Although the mechanism of action of the topical medicinal plant products provides a rationale basis for their use in the treatment of osteoarthritis, the quality and quantity of current research studies of effectiveness are insufficient. Arnica gel probably improves symptoms as effectively as a gel containing non-steroidal anti-inflammatory drug, but with no better (and possibly worse) adverse event profile. Comfrey extract gel probably improves pain, and Capsicum extract gel probably will not improve pain or function at the doses examined in this review. Further high quality, fully powered studies are required to confirm the trends of effectiveness identifed in studies so far.

Common complementary and alternative therapies with potential use in dermatologic surgery: risks and benefits

BACKGROUND

Ambulatory surgery patients often use complementary and alternative medicine (CAM) therapies. CAM therapies may create beneficial and detrimental perioperative conditions.

OBJECTIVE

We sought to improve knowledge of CAM effects in dermatologic surgery, allowing dermatologists to potentially capitalize on therapeutic actions and to mitigate complications.

METHODS

PubMed literature search of CAM therapies in dermatologic and surgical settings was performed. Common CAM therapies with possible effects on dermatologic surgery were selected. Beneficial and detri-mental effects were reviewed.

RESULTS

A myriad of products may be used perioperatively by the patient. Therapies appearing to have some evidence for potential benefit include bromelain, honey, propolis, arnica, vitamin C and bioflavonoids, chamomile, aloe vera gel, grape seed extract, zinc, turmeric, calendula, chlorella, lavender oil, and gotu kola. Potential complications vary according to product and include platelet inhibition, contact dermatitis and, in rare cases, systemic toxicity.

LIMITATIONS

This review focuses on CAM having significant published studies evaluating efficacy for wound healing, anti-inflammatory, antipurpuric, or perioperative-related use. Most published studies have been small and often have design flaws. The scope of CAM is large and not all therapies are discussed.

CONCLUSION

Selected CAM therapies have been reported to promote wound healing, reduce edema or purpura, and provide anti-inflammatory effects. Because of high rates of CAM use, surgeons should familiarize themselves with common uses, potential benefits, and complications. Further study of effects in the dermatologic surgery setting may improve the patient-doctor relationship and enhance outcomes.

The Effect of Topical Arnica on Muscle Pain

Background:

The herb Arnica montana, in topical formulations, has been reputed to decrease bruising and muscle pain. This claim has been inadequately and incompletely addressed.

Objective:

To determine whether topical A. montana cream could decrease subjective leg pain following calf raises. Secondary outcomes were effects on ankle range of motion and muscle tenderness.

Methods:

A randomized, double-blind, placebo-controlled trial was conducted in 53 subjects. Active range of motion was measured in both ankles, and then a series of calf-raises were completed according to a standardized protocol. Each participant received 2 tubes of cream, 1 with active arnica and 1 with placebo. The creams were applied to the lower legs immediately after the exercise, and again at 24 and 48 hours postexercise according to the “RIGHT” or “LEFT” labels. At 48 hours postexercise, subjects had their ankle range of motion and muscle tenderness measured. Subjects used the analog scale to rate pain in each leg at baseline, 24 hours, 48 hours, and 72 hours.

Results:

No significant differences in pain scores were seen before exercise (arnica: 0.07 vs placebo: 0.09, p = 0.32). Pain scores on legs treated with arnica were higher than scores on those receiving placebo 24 hours after exercise (3.04 vs 2.36, respectively; p < 0.005). Pain scores on day 3 (arnica: 3.44 vs placebo: 3.20, p = 0.66) and day 4 (arnica: 2.36 vs placebo: 2.31, p = 0.62) were not significantly different. There was no difference in muscle tenderness (arnica: 1.05 vs placebo: 1.05, p = 1.0). Ankle range of motion did not differ significantly on either day 1 (arnica: 64.70 degrees vs placebo: 66.15, p = 0.352 or day 3 (arnica: 63.32 degrees vs placebo: 65.94, p = 0.058).

Conclusions:

Rather than decreasing leg pain, arnica was found to increase leg pain 24 hours after eccentric calf exercises. This effect did not extend to the 48-hour measurement.